Python if statement expected an indented block

IndentationError: expected an indented block

In documentation terminology, indentation means the space from margin to the begin of characters in a line. In most popular programming languages, spaces or indentation are just used to make the code look better and be easier to read. In Python , it is actually part of this programming language. Because the Python language is a very sensitive language for indentation, it has caused confusion for many beginners. Putting in an extra space or leaving one out where it is needed will surely generate an error message . Some common causes of this error include:

1. Forgetting to indent the statements within a compound statement
2. Forgetting to indent the statements of a user-defined function.

The error message IndentationError: expected an indented block would seem to indicate that you have an indentation error. It is probably caused by a mix of tabs and spaces . There are two main reasons why you could have such an error:

output

The above example fails to indent after the if statement and the output states that you need to have an indented block on line 2.

example 2:

The output states that you need to have an indented block on line 4, after the else: statement

Python block

Here you can see, what follows the colon (:) is a line-break and an indented block . Python uses white-space to distinguish code blocks. You can use spaces or tabs to create a Python block . When several statements use the same indentation , they are considered as a block. Python in fact insists that separate statements use the same indentation in a block. It would complain if you forget to indent when a block is expected, as well as if you use varying indentations.

Indentation in Python

The indentation can be any consistent white space . It is recommended to use 4 spaces for indentation in Python, tabulation or a different number of spaces may work, but it is also known to cause trouble at times. 4 spaces are a good compromise between small indentation (allows greater nesting depth) and large indentation (easier to read). Using only spaces is generally the better choice. Most editors have an option for automatically converting tabs to spaces. If your editor has this option, turn it on.

Tabbed indentation

Tabs are a bad idea because they may create different amount if spacing in different editors . They’re also potentially confusing if you mix tabbed indentation with spaced indentation. If you’re using an IDE like Eclipse , you can configure how many spaces the IDE will insert when you press tab. It’s important to note that most modern IDEs help you keep indentation using tabs or spaces , but since whitespace characters are not visible in some editors, you should take care to properly indent blocks .

Docstring Indentation

This error IndentationError: expected an indented block can also come up if the programmer forgets to indent a docstring. Docstrings must be in line with the rest of the code in a function. Docstring processing tools will strip a uniform amount of indentation from the second and further lines of the docstring, equal to the minimum indentation of all non-blank lines after the first line.

output

To fix this issue, indent the docstring .

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IndentationError: expected an indented block

As the error implies, this occurs after statements that require indenting, such as after if statements, for loops and try except exception handling.

Unlike many programming languages that use braces, Python requires indents to determine which code block belongs to a statement. More simply, after detecting the : character in your script, Python will look for an indent.

This lesson will quickly examine a few reasons when this error can occur and how to fix it.

Cause 1: Unindented Statement

Imagine you are looking at sales figures for Company A, which sells software packages. You want to write a script for determining which employees are meeting a certain sales threshold.

Using enumerate , we can iterate through employees and use the index as an ID for each employee. We can then print off a message showing if that employee hit the sales target or not.

The script below shows how we can execute this process:

Although we’ve made the if else loop correctly, the for statement is causing an indentation error. This error is happening because we’ve provided a list for Python to iterate through in our for loop, but it doesn’t know which logic it needs to apply while looping.

The straightforward fix is to add an indent at the line indicated in the error:

Solution

Now that Python has the correct structure, it will check the sales figure for each employee individually and consider if the number is greater than 50 or not. It will then print the corresponding message and move on to the next employee.

Cause 2: Empty Suite

When working on larger scripts, you’ll often anticipate many if elif branches ahead of time by creating a branch and commenting on some logic you plan on filling in later.

Here’s an example using our sales analysis script that we used previously:

In this case, Python throws the error because it’s looking for a code block after the if statement, i.e., what your program should do if the statement is true. The code seems to be structured correctly, but the program will fail to run until the actual code is placed after the if .

Having a statement like this without anything following it is known as an empty suite. A quick fix for this is to use the pass keyword:

Solution

In this situation, the pass keyword allows Python to skip when the if is true. This command bypasses the indentation error, allowing us to work on other areas until we are ready to come back and write the functionality that displays a message.

Cause 3: Unindented Docstring

To keep code well-documented, we can use docstrings at the start of a function, class, or method to quickly say what the code does. This description is to make life easier for yourself and others when reviewing the code later.

To write a docstring, you use two sets of triple apostrophes (»’) or quotes («»»), which makes multi-line comments in Python possible.

The example below shows how we can use a docstring to describe a function to contain the if-else loop we’ve been using in our sales analysis script.

This script crashed because Python is looking for indentation at the start of the function. To fix this, we can add an indent to the docstring. Shown below is this solution in action:

Solution

Note that in this example, using a regular comment (#) to mark the docstring would prevent the indentation error without the need to add an indent. Avoid doing this, though, as it’s best practice to keep docstrings within two sets of triple apostrophes/quotes.

Summary

This error occurs when Python is looking for an indented block of code after certain types of statements. The indented block tells Python that the code within the block is relevant to the statement. This s>tructure is fundamental to the Python programming language, so it’s no surprise incorrectly indenting things can make scripts malfunction! Luckily, this is an easy fix, and in most cases, all you need to do is quickly add an indent in the correct place, and you’ll be good to go.

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How to Fix IndentationError: expected an indented block

IndentationError: expected an indented block error occurs in Python when the code is not indented correctly.

To fix the IndentationError: expected an indented block error in Python, “indent the code block correctly to align it with its surrounding code.”

In Python, whitespace (indentation) is significant and determines the scope of a code block.

An “IndentationError: expected an indented block” means a block of code that is supposed to be indented at all or not indented enough, leading the interpreter to believe that the block of code is not part of the current scope.

Before Python runs any code in your program, it will first discover each line’s correct parent and children. Then, Python throws an Indentation whenever it comes across a line for which it cannot define the right parent to assign.

Reproduce the error

def compare(num): if num >= 1: print("It is positive number") elif num < 0: print("It is negative number") else: print("It is zero") compare(1)

If you run the above file, your output looks like the one below.

 File "/Users/krunal/Desktop/code/pyt/database/app.py", line 3 print("It is positive number") ^ IndentationError: expected an indented block

Other causes of the error

The causes of the IndentationError: expected an indented block error include:

1. Incorrect indentation levels: T he code is not indented to the proper level
2. Mixing tabs and spaces for indentation causes inconsistencies, leading to the error message.
3. Improper use of white space characters: Using extra spaces or the wrong type of white space character can result in an error.

How to Fix IndentationError: expected an indented block

Python cares about indention

In Python, indentation replaces the keyword begin / end or < >and is therefore necessary.

This is verified before the execution of the code; therefore, even if the code with the indentation error is never reached, it won’t work.

From the above example, you can check if you have left alone an elif: part of an if-condition, and check if the indentation is missing after conditions, loops, etc.

In our example, there should be an indentation before starting a new statement after the if, elif, and else blocks.

Still, we did not put any whitespace, and that caused an indentation error. So let’s resolve the error by providing whitespaces.

def compare(num): if num >= 1: print("It is positive number") elif num < 0: print("It is negative number") else: print("It is zero") compare(1)

And the IndentationError is successfully resolved.

For example, Python statements start with def or must have at least one child. This means that a function must have at least one line of code. It also means that a conditional must have at least one line of code to run if the condition is True.

Let’s see the example in which we don’t write anything after the first if statement.

def compare(num): if num >= 1: elif num < 0: print("It is negative number") else: print("It is zero") compare(1)

File "/Users/krunal/Desktop/code/pyt/database/app.py", line 4 elif num < 0: ^ IndentationError: expected an indented block

After Python reads the if statement, it expects to see at least one child line following it. However, since the next non-empty line reads it is the elif statement, which means the if statement has no children, Python reports that it expected some indented lines.

To fix this IndentationError, either place at least one line of code as the if statement’s child or remove them entirely.

def compare(num): if num >= 1: print("It is positive number") elif num < 0: print("It is negative number") else: print("It is zero") compare(1)

If you run the above code, you will get the expected output.

Python unexpected indent

Python throws an IndentationError when it finds a line indented as if the line had some parent line, but it couldn’t get any lines above to be its parent.

For example, you face this unexpected indent error when a line is indented by one or more spaces more than the previous line, and the previous line isn’t def, if, elif, else, for, or while loop.

That is it for IndentationError in Python and how to resolve it.

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